1. Preheat the oven to 350 degrees F.
2. Place the hazelnuts on a large, heavy baking sheet, and toast in the oven, stirring occasionally, until the nuts are fragrant and light golden brown in the center, about 7 minutes. Let cool completely.
3. Rub the hazelnuts between your palms to remove the dark skins from the nuts.
4. In the bowl of a food processor, pulse the nuts just until they are coarsely chopped then set them aside.
5. Meanwhile, bring a large pot of salted water to a boil. Add the oil, then the ravioli and cook until the ravioli float to the top, about 4 minutes.
6. Using a slotted spoon, transfer the ravioli to a large platter and tent with foil to keep warm.
7. In a small, heavy skillet, melt the butter over medium heat until it starts to brown, about 3 minutes. Add the sage leaves and fry until they are crisp and fragrant, about 20 seconds. Remove from the heat and stir in the nutmeg.
8. Pour the butter sauce over the ravioli and sprinkle with the toasted hazelnuts and Parmesan cheese. Grate the amaretti cookies over the ravioli and serve immediately.